Glaucoma is a group of diseases, frequently characterized by raised intraocular pressure (IOP), which affects the optic nerve, and is the second leading cause of blindness in the world. Currently, most glaucoma patients are initially managed with medical therapy. However, some patients still require surgical interventions to preserve their vision. When glaucoma continues to progress despite the use of medication regimes and possibly laser treatments (ALT or SLT treatments), a glaucoma filtration procedure (trabeculectomy) may be recommended. Additional surgical techniques for reducing intraocular pressure (IOP) include laser trabeculoplasty, non-penetrating filtration surgery (i.e. deep sclerectomy, viscocanalostomy), shunts, and cyclo-destructive procedures.
Deep sclerectomy, a non-penetrating or minimally invasive filtering surgery, is being proposed as a viable alternative to conventional trabeculectomy. In contrast to trabeculectomy, which is associated with significant morbidity, deep sclerectomy does not penetrate the eye, and has been shown to minimize intraoperative and postoperative complications.
In a manual non-penetrating deep sclerectomy (NPDS) procedure performed with manual surgical instruments, a deep scleral flap is first dissected and then a second scleral layer is cut out, leaving an exposed thin layer of trabecular meshwork and Descemet's membrane. Fluid percolation through the remaining tissue is the desired outcome of the procedure. Inadvertent perforation of the thin trabeculo-descemet membrane or alternatively an insufficiently deep second scleral flap, are relatively frequent complications, occurring in about 30% of the cases in the early stages of the learning curve of this procedure. In the case of perforation, the procedure may be converted to a conventional trabeculectomy; however, the high rates of perforation and a long learning curve limit the use of deep sclerectomy as a common treatment procedure. While the risk of perforation is relatively high, if the tissue is not cut deep enough, the filtration may not be effective and the intraocular pressure will not be reduced to the desired level. Since the scleral tissue needs to be dissected to more than 90% of its depth, leaving a residual intact layer of only several tens of microns, the procedure is very demanding and requires significant skills and expertise.
The following publications may be relevant to this application:
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